Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

State of Himalayan glaciers less alarming than feared

20.04.2012
Several hundreds of millions of people in Southeast Asia depend, to varying degrees, on the freshwater reservoirs of the Himalayan glaciers.
Consequently, it is important to detect the potential impact of climate changes on the Himalayan glaciers at an early stage. Together with international researchers, glaciologists from the University of Zurich now reveal that the glaciers in the Himalayas are declining less rapidly than was previously thought. However, the scientists see major hazard potential from outbursts of glacial lakes.

Ever since the false prognoses of the Intergovernmental Panel on Climate Change (IPCC), the Himalayan glaciers have been a focus of public and scientific debate. The gaps in our knowledge of glaciers in the Himalayan region have hindered accurate statements and prognoses. An international team of researchers headed by glaciologists from the University of Zurich and with the involvement of scientists from Geneva now outlines the current state of knowledge of glaciers in the Himalayas in a study published in Science. The scientists confirm that the shrinkage scenarios for Himalayan glaciers published in the last IPCC report were exaggerated.
Glacier area 20 percent smaller than assumed
The most up-to-date mappings so far based on satellite data revealed that glaciers in the Himalayas and Karakoram cover a total area of approximately 40,800 km². While this is around twenty times larger than all glaciers of the European Alps put together, it is as much as twenty percent smaller than was previously assumed. Lead scientist Tobias Bolch, who researches at the University of Zurich and Dresden University of Technology, mainly puts this down to erroneous mappings in earlier studies.
Less shrinkage than predicted
The scientists took all the existing measurements of length, area and volume changes and mass budgets into account for their study. While some of the measurement series on length changes date back to 1840, measurements of glacier mass budget that instantaneously reflect the climate signal are rare. In addition, continuous measurement series do not stretch back any further than ten years. The researchers recorded average length decreases of 15 to 20 metres and area decreases of 0.1 to 0.6 percent per year in recent decades. Furthermore, the glacier surfaces lowered by around 40 centimetres a year. “The detected length changes and area and volume losses correspond to the global average,” explains Bolch, summarizing the new results. “The majority of the Himalayan glaciers are shrinking, but much less rapidly than predicted earlier.”

Aerial view of the Imja glacier and Lake Imja, Nepal, the Himalayas. The lake appeared in the 1960s and has grown continuously ever since. The sinking of the surface of the debris-covered glacier tongue is also clearly discernible. Picture: J. Kargel, University of Arizona.


The large glacial lake Imja Thso in the Imja Valley south of Mt. Everest/Nepal formed in the 1960s and has grown continuously ever since. 3D view generated from an ASTER satellite image. Picture: T. Bolch, Universität Zürich/TU Dresden

For the regions in the northwestern Himalayas and especially in the Karakoram Range, the researchers noted very heterogeneous behaviour in the glaciers. Many of them are dynamically unstable and prone to rapid advances (so called “surges”) that largely occur independently of the climatic conditions. For the last decade on average, even a slight volume increase was detected. Based on their analyses, the researchers assume that glacier shrinkage will not have a major impact on the water drainage of large rivers like the Indus, Ganges and Brahmaputra in the coming decades.

Greater variability and menacing flooding of glacial lakes
Despite the partial all-clear for the Himalayan glaciers, however, Bolch advises caution: “Due to the expected shrinkage of the glaciers, in the medium term we can expect a greater variability in the seasonal water drainage. Individual valleys could dry up seasonally.”

Bolch and his colleagues also see a very serious threat to the local population in newly formed or rapidly growing glacial lakes. The deluge of water and debris from potential outbursts of these lakes could have devastating consequences for low-lying regions. According to the scientists, increased efforts are urgently needed to monitor the lakes as well as changes in the glaciers and the climate in the Himalayas.

The study was conducted as part of the EU project High Noon and the European Space Agency project Glaciers_cci.

Literature:
T. Bolch, A. Kulkarni, A. Kääb, C. Huggel, F. Paul, J.G. Cogley, H. Frey, J.S. Kargel, K. Fujita, M. Scheel, S. Bajracharya, M. Stoffel. The State and Fate of Himalayan Glaciers. Science. April 20, 2012. doi: 10.1126/science.1215828.
Contact:
Dr. Tobias Bolch
Department of Geography
University of Zurich
Tel.: +41 44 635 52 36
Email: tobias.bolch@geo.uzh.ch

Nathalie Huber | Universität Zürich
Further information:
http://www.uzh.ch

More articles from Earth Sciences:

nachricht Ice cave in Transylvania yields window into region's past
28.04.2017 | National Science Foundation

nachricht Citizen science campaign to aid disaster response
28.04.2017 | International Institute for Applied Systems Analysis (IIASA)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>